Buggy code:
public class Util { private static int CAPITAL_BASE = 64 ; private static int SMALL_BASE = 96 ; private static boolean displayToastFlag = false ; private static List < String > originalDataList = new ArrayList < String > ( ) ; public static void displayToast ( Context context , CharSequence cs ) { } public static void displayToast ( Context context , CharSequence cs , boolean flag ) { } public static boolean isSolved ( ArrayAdapter < CharSequence > adapter ) { } public static List < String > prepareNumberList ( int length ) { } public static List < String > prepareAlphaList ( int length , int alphaOption ) { } public static String prepareHelpText ( ) { StringBuffer sb = new StringBuffer ( ) ; <START_BUG> sb . append ( "Play<seq2seq4repair_space>this<seq2seq4repair_space>game<seq2seq4repair_space>by<seq2seq4repair_space>sliding<seq2seq4repair_space>tile<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n\n" ) . append ( "When<seq2seq4repair_space>tiles<seq2seq4repair_space>are<seq2seq4repair_space>arranged<seq2seq4repair_space>in<seq2seq4repair_space>correct<seq2seq4repair_space>order<seq2seq4repair_space>you<seq2seq4repair_space>win.\n\n" ) . append ( "You<seq2seq4repair_space>have<seq2seq4repair_space>options<seq2seq4repair_space>of<seq2seq4repair_space>playing<seq2seq4repair_space>game<seq2seq4repair_space>with<seq2seq4repair_space>numbers<seq2seq4repair_space>or<seq2seq4repair_space>alphabets.\n\n" ) . append ( "Number<seq2seq4repair_space>game<seq2seq4repair_space>has<seq2seq4repair_space>three<seq2seq4repair_space>options<seq2seq4repair_space>to<seq2seq4repair_space>play<seq2seq4repair_space>with<seq2seq4repair_space>9,<seq2seq4repair_space>16<seq2seq4repair_space>or<seq2seq4repair_space>25<seq2seq4repair_space>tiles.\n\n" ) . append ( "Alphabet<seq2seq4repair_space>game<seq2seq4repair_space>has<seq2seq4repair_space>three<seq2seq4repair_space>options<seq2seq4repair_space>to<seq2seq4repair_space>play<seq2seq4repair_space>with<seq2seq4repair_space>CAPITAL,<seq2seq4repair_space>small<seq2seq4repair_space>or<seq2seq4repair_space>mIxED<seq2seq4repair_space>letters.\n\n" ) . append ( "Moreover<seq2seq4repair_space>there<seq2seq4repair_space>are<seq2seq4repair_space>two<seq2seq4repair_space>variants<seq2seq4repair_space>of<seq2seq4repair_space>the<seq2seq4repair_space>game.\n" ) . append ( "<seq2seq4repair_space>1.<seq2seq4repair_space>Easy:<seq2seq4repair_space>Any<seq2seq4repair_space>tile<seq2seq4repair_space>can<seq2seq4repair_space>be<seq2seq4repair_space>moved<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n" ) . append ( "<seq2seq4repair_space>2.<seq2seq4repair_space>Challanging:<seq2seq4repair_space>Only<seq2seq4repair_space>adjacent<seq2seq4repair_space>tile<seq2seq4repair_space>can<seq2seq4repair_space>be<seq2seq4repair_space>moved<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n\n" ) ; <END_BUG> return sb . toString ( ) ; } public static boolean isValidMove ( int numberOfColumns , int blankTileId , int position ) { } public static int swapTiles ( ArrayAdapter < CharSequence > adapter , int blankTileId , int position ) { } public static int randInt ( Random rand ) { } public static void saveScoreWindow ( Activity act , final String timeElapsed , final String gameType ) { } public static void writeFile ( String record ) { } public static void sortLine ( ) throws Exception { } private static String getField ( String line ) { } }

Fix:
sb . append ( "Play<seq2seq4repair_space>this<seq2seq4repair_space>game<seq2seq4repair_space>by<seq2seq4repair_space>sliding<seq2seq4repair_space>tile<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n\n" ) . append ( "When<seq2seq4repair_space>tiles<seq2seq4repair_space>are<seq2seq4repair_space>arranged<seq2seq4repair_space>in<seq2seq4repair_space>correct<seq2seq4repair_space>order<seq2seq4repair_space>you<seq2seq4repair_space>win.\n\n" ) . append ( "You<seq2seq4repair_space>have<seq2seq4repair_space>options<seq2seq4repair_space>of<seq2seq4repair_space>playing<seq2seq4repair_space>game<seq2seq4repair_space>with<seq2seq4repair_space>numbers<seq2seq4repair_space>or<seq2seq4repair_space>alphabets.\n\n" ) . append ( "Number<seq2seq4repair_space>game<seq2seq4repair_space>has<seq2seq4repair_space>three<seq2seq4repair_space>options<seq2seq4repair_space>to<seq2seq4repair_space>play<seq2seq4repair_space>with<seq2seq4repair_space>9,<seq2seq4repair_space>16<seq2seq4repair_space>or<seq2seq4repair_space>25<seq2seq4repair_space>tiles.\n\n" ) . append ( "Alphabet<seq2seq4repair_space>game<seq2seq4repair_space>has<seq2seq4repair_space>three<seq2seq4repair_space>options<seq2seq4repair_space>to<seq2seq4repair_space>play<seq2seq4repair_space>with<seq2seq4repair_space>CAPITAL,<seq2seq4repair_space>small<seq2seq4repair_space>or<seq2seq4repair_space>mIxED<seq2seq4repair_space>letters.\n\n" ) . append ( "Moreover<seq2seq4repair_space>there<seq2seq4repair_space>are<seq2seq4repair_space>two<seq2seq4repair_space>variants<seq2seq4repair_space>of<seq2seq4repair_space>the<seq2seq4repair_space>game.\n" ) . append ( "<seq2seq4repair_space>1.<seq2seq4repair_space>Easy:<seq2seq4repair_space>Any<seq2seq4repair_space>tile<seq2seq4repair_space>can<seq2seq4repair_space>be<seq2seq4repair_space>moved<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n" ) . append ( "<seq2seq4repair_space>2.<seq2seq4repair_space>Challenging:<seq2seq4repair_space>Only<seq2seq4repair_space>adjacent<seq2seq4repair_space>tile<seq2seq4repair_space>can<seq2seq4repair_space>be<seq2seq4repair_space>moved<seq2seq4repair_space>to<seq2seq4repair_space>open<seq2seq4repair_space>slot.\n\n" ) ;